From: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx> A list of MGID/MLID pairs is built when doing a multicast attach. When the multicast detach is called, the list is searched, and regardless of the search outcome, the driver detach is called. If an MGID/MLID pair is not on the list, driver detach should not be called, and an error should be returned. Calling the driver without removing an MGID/MLID pair from the list can leave the core and driver out of sync. Fixes: f4e401562c11 ("IB/uverbs: track multicast group membership for userspace QPs") Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> --- drivers/infiniband/core/uverbs_cmd.c | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index b9024fa..27fcbeb 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -2647,6 +2647,7 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file, struct ib_qp *qp; struct ib_uverbs_mcast_entry *mcast; int ret = -EINVAL; + bool found = false; if (copy_from_user(&cmd, buf, sizeof cmd)) return -EFAULT; @@ -2658,18 +2659,22 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file, obj = container_of(qp->uobject, struct ib_uqp_object, uevent.uobject); mutex_lock(&obj->mcast_lock); - ret = ib_detach_mcast(qp, (union ib_gid *) cmd.gid, cmd.mlid); - if (ret) - goto out_put; - list_for_each_entry(mcast, &obj->mcast_list, list) if (cmd.mlid == mcast->lid && !memcmp(cmd.gid, mcast->gid.raw, sizeof mcast->gid.raw)) { list_del(&mcast->list); kfree(mcast); + found = true; break; } + if (!found) { + ret = -EINVAL; + goto out_put; + } + + ret = ib_detach_mcast(qp, (union ib_gid *)cmd.gid, cmd.mlid); + out_put: mutex_unlock(&obj->mcast_lock); uobj_put_obj_read(qp);